Process of forming and sharpening drill-bits and the like.



H. J. H. NATHORST & G. LUNDSTRO'M. PROCESS 0E- FORMING AND SHARPENINGDRILL BITS AND THE LIKE.

' APPLICATION FILED DEC. 7, 1909.

1,094,807, Patented Apr. 28, 1914.

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UNITED STATES PATENT @FFIQE.

HARRY JOHAN HJALMAR NATHORST AND GO'ITHAR-D LUNDSTRSM, OF GELLIVABE.IVIALMFALI, MAIJMBERGET, SVEDEN, ASSIGNORS, BY MESNE. ASSIGNMENTS, 'IONYA AKTIEBOLAGET ALTAS, OF STOCKHOLM, SWEDEN.

PROCESS OF FORMING AND SI-IARPENING DRILL-BITS AND THE LIKE.

To (4 whom it may concern 4J6 it known that we, HARRY JOI-IAN HaamnvnNarnonsr and Go'rrnano Lonns'rnoll, subjects of the King of Sweden,residing at Gellivare Malmtalt, Malmberget, Sweden, have jointlyinvented new and useful Improvements in Processes of Forming andSharpening Drill-Bits and the like, of which the following is aspecification, reference being had to the drawing accompany ing andforming a part hereof.

This invention relates to an improved process of forming or sharpeningcutting edges on drill bits or other similar tools.

In forming or sharpening cutting edges on drill bits and the like,especially cruciform drill bits, so-called star bits, used in rockdrills, a machine is usually employed having a stamp which is caused bysuitable means to cut into the drill bit. In machines of this kindhitherto used the drill bit was placed in the machine in alinement withthe stamp and the latter was thus caused to cut into the drill bit inits longitudinal .direction. In these machines it is di'flicult, onaccount of the resistance of the hard drill bit, to form the cuttingedges in one heating. On account thereof, it has usually been necessaryto repeatedly heat and work the bit in the machine. This procedure istimewasting and disadvantageous in respect to the durability of thedrill bit.

The object of this invention is to enable the cutting edges of the bitto be formed or the sharpening to be effected with less labor and in oneheating.

The invention consists, chiefly, in forming and sharpening the cuttingedges by operating the heated drill bit by a rotary stamp moving at anangle to the drill bit, and turning the stamp and the drill bit duringthe said operation so as to expose the end of the drill bit all around,or to such an extent as is required for obtaining the desired teeth. tothe action of the stamp for cutting and sharpening the drill bit in oneheating.

In carrying the invention into effect, the drill bit is suitably placedin a machine in such a position that the axis of the drill bit forms anangle less than 30 with the axis of the stamp. By this means only one ofthe teeth of the stamp will cut at a time into the drill bit and thewhole power of the Specification of Letters Patent.

Application filed December 7, 1909.

Patented Apr. 28, 1914.

Serial No. 531,806.

machine will thus be applied only on a small part of the drill bit at atime, by which the end of the drill bit is more easily split and pressedout. In order to conveniently cut the drill bit all aroundwithoutreheating, the stamp is rotated about its axis and the drill bitis pressed against the stamp in such a manner as to be able to rotateabout its axis, by which the drill bit will be caused to partake in therotation of the stamp. The rotation of the stamp may be performed bymachine power or by hand. Obviously, the same action may be obtained bydirectly turning the drill bit, while the stamp is rotated by the drillbit bearing thereon.

The invention further comprises the construction and combination ofparts hereinafter more particularly described.

The invention is illustrated in the drawing which shows schematically,viewed from above, amachine by which our improved process may be carriedinto effect.

Referring to the drawing, the machine consists of a pneumatic hammer thefore part a of which is shown in the drawing. Inserted in the saidmachine is a stamp 79 adapted to cut into the end of the drill bit 0which is rotatably placed in a suitable holder (not shown). Thepneumatic hammer and the holder are suitably adjustable relatively toeach other in such a manner that the angle of inclination between theaxis of the stamp and that of the drill bit may be changed. The stamp I)which is inserted in a suitable rotating device in the machine is causedto operate the drill bit by impacts from a reciprocating hammer (notshown). Obviously, the stamp may be connected directly to the hammer, ifdesired. In the embodiment shown, the stamp is provided with six cuttingedges. The drill bit is mounted so that its axis or center line :0 formsan angle less than 30 with the axis or center line 2 of the stamp.During the rotation of the stamp about is axis it causes the drill bitto rotate and thereby cuts with one edge after the other into the end ofthe drill bit so that the whole power of the machine is applied on oneedge after the other.

According as the drill bit is operated upon by the stamp it will benecessary, in order that the stamp shall always hear on.

the drill bit, to cause the hammer and the stamp or the drill bit to besuccessively fed forward. In each case the relative movement shouldobviously be such that the center lines will always maintain the sameangle of inclination to each other and the center (Z of the stamp willalways be in the center line :0 of the drill bit. To this end the stampand its actuating parts may be mounted on a slide moving during thesharpening operation along" the center line a; of the drill bit, or thelatter mav for the same purpose be mounted on a slide movable parallelto the center line of the stamp. In the drawing the former arrangementis supposed to be used (the part of the machine carrying the stamp isshown by dotted lines in the position which it will finally take up).

We claim:

The process of forming and sharpening cutting edges on drill bits andthe like Which consists in heating the drill bit and holding it so thatit may rotate, operating upon the same by a stamp moving at an angle tothe axis of the drill bit and rotating one of said parts in contact withthe other thus inr parting rotary motion to the latter during the saidoperation.

HARRY JOHAN HJALMAR Nll'll'lllRS'l. GOTTHARD LUNDSTRGM. lVitnessesrsrroo GoLnnUNn, A. F. DAHNY.

topics or this patent may be obtained for five cents each, by addressingthe Commissioner of Patents, Washington, D. C.

Correction in Letters Patent No. 1,094,807.

It is hereby certified that the assignee in Letters Patent No.1,094,807, granted April 28, 1914;, upon the application of Harry JohanHjalmar Nathorst and Gotthard Lundstrom, of Gellivare Malmfalt,Malmberget, Sweden, for an improvement in Processes of Forming andSharpening Drill-Bits and the Like, was erroneously described andspecified as Nya Aktiebolaget Altas, Whereas it should have beendescribed and specified as Nya Alctiebolaget Atlas, as shown by therecords of assignments in this office; and that the said Letters Patentshould be read with this correction therein that the same may conform tothe record of the case in the Patent Ofiice.

Signed and sealed this 7th day of July, A. D., 1914:.

[SEAL] R. F. WHITEHEAD,

Acting Commissioner of Patents.

